<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>p3_css常用值</title>
    <style>
        h1{
            color:red;
            color:rgb(255,0,0);
            color:rgb(0,255,255);
            color:rgb(0,255,0);
            color:rgb(255,0,255);
            color:rgb(0,0,255);
            color:rgb(255,255,0);
            color:rgb(255,255,255);
            color: rgb(0,0,0);

            color: #ff0000;
            color: #00ff00;
            color: #0000ff;
            color: #00f;

            color: rgba(255,0,0,1);
            color: rgba(255,0,0,.5);
            color: rgba(255,0,0,0.1);
            /*color: rgba(255,0,0,0);*/

        }

        /*块级元素默认宽度为父级宽度的100%，高度0靠内容撑起来*/
        .d1{
            width: 50px;
            height: 100px;
            /*插入背景图*/
            background-image: url(img/mr.png);
            background-size: 50px 100px;
            background-color: darkkhaki;
        }
        .d2{
            width: 500px;
            height: 300px;
            border: 5px solid red;
            background-image: url("img/mr.png");
            background-repeat: no-repeat;
            background-position: 0 0;
            background-position: 50px 0;
            background-position: center center;
            background-position: center;
            background-position: 50% 50%;
            background-position: 100% 100%;
        }

        .d3{
            width: 500px;
            height: 300px;
            background-image: linear-gradient(30deg,red,orange,yellow,green,blue);
        }
    </style>

</head>
<body>
    <h1>测试颜色</h1>
<!--  .d*3 .d class选择器 默认div  -->
    <div class="d1"></div>
    <div class="d2"></div>
    <div class="d3"></div>
</body>
</html>